1. Technical Field
The present invention relates to a crawlspace vent with flood flaps that permit flood waters to pass in and out of a sealed crawlspace under a building in the event of a flood, yet inhibit air flow through the sealed crawlspace the rest of the time.
2. Background Information
Many builders and homeowners in the last decade are realizing the advantages of sealing the crawlspace under their new construction, or converting the crawlspace under an existing building to a sealed crawlspace. With dehumidifiers operating in the crawlspace, usually under the control of a humidistat, such advantages include reduced humidity and a relatively constant temperature in the crawlspace, which result in lower heating and cooling bills for the building, reduced mold, fungus, and mildew under the building, and fewer problems from small animals entering through the crawlspace. Conventional air vents are disadvantageous with a sealed crawlspace, because dehumidifiers under the building will not work as well with an influx of humid outside air entering the crawlspace through conventional air vents.
However, houses and other buildings built in a flood-prone area require some sort of crawlspace venting to prevent the building walls from weakening or collapsing during a flood event. Without vents that permit flood waters to flow in and out of the crawlspace under a building, hydrostatic pressure in the crawlspace can reach a break point beyond which the building walls may crumble. It has therefore been impossible to seal a crawlspace in a building on a flood plain heretofore while complying with government rules and regulations. Up to this point, there have not been any cost-effective vents that obstruct air flow completely and provide insulation, yet allow water to flow into and out of a sealed crawlspace.
Buildings located in areas where flooding is a possibility are generally required to have vents in the walls of their crawlspaces to allow flood waters to flow in to and out of the crawlspace in order to relieve hydrostatic pressures that could destroy the integrity of the walls. In all buildings with crawlspaces, whether in a flood zone or not, crawlspace vents are used to allow air flow to avoid dampness under the building, which can cause rotting, insect infestation, moisture buildup, etc. The new sealed crawlspace can be installed as a building is being constructed or retroactively. The sealed crawlspace provides a dry, clean and heating and air conditioning efficient building. The flood flaps vent 10 opens to permit the flow of water in or out of the building when the water level outside (or inside) the building rises, thereby avoiding an excessive pressure differential to develop between the interior and exterior of the building, as well as damage or failure of the building while maintaining a sealed vent when high water conditions do not exist.
Rules and regulations now require buildings with enclosed spaces located below defined flood plain levels to include automatic equalization of interior and exterior hydrostatic pressure caused by flood waters. The rules and regulations require buildings to be designed and built to allow flood water to move in and out of a building freely. Unfortunately, the vents developed for flood purposes cannot provide the insulated and sealed conditions required by sealed crawlspace technology. A number of devices have been developed to reduce or eliminate the pressure differential that may develop between the interior and exterior of a building.
The flood flaps vent of the present invention maintains a sealed crawlspace environment by blocking air flow through the vent, yet permitting water to flow in and out of the crawlspace freely during a high water event. In a building with flood flaps vents, hydrostatic pressure does not reach a break point and structural integrity of the building is maintained.